diff options
Diffstat (limited to 'src/lib/tlslite/utils/OpenSSL_AES.py')
-rwxr-xr-x | src/lib/tlslite/utils/OpenSSL_AES.py | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/src/lib/tlslite/utils/OpenSSL_AES.py b/src/lib/tlslite/utils/OpenSSL_AES.py new file mode 100755 index 000000000..e60679bf5 --- /dev/null +++ b/src/lib/tlslite/utils/OpenSSL_AES.py @@ -0,0 +1,49 @@ +"""OpenSSL/M2Crypto AES implementation.""" + +from cryptomath import * +from AES import * + +if m2cryptoLoaded: + + def new(key, mode, IV): + return OpenSSL_AES(key, mode, IV) + + class OpenSSL_AES(AES): + + def __init__(self, key, mode, IV): + AES.__init__(self, key, mode, IV, "openssl") + self.key = key + self.IV = IV + + def _createContext(self, encrypt): + context = m2.cipher_ctx_new() + if len(self.key)==16: + cipherType = m2.aes_128_cbc() + if len(self.key)==24: + cipherType = m2.aes_192_cbc() + if len(self.key)==32: + cipherType = m2.aes_256_cbc() + m2.cipher_init(context, cipherType, self.key, self.IV, encrypt) + return context + + def encrypt(self, plaintext): + AES.encrypt(self, plaintext) + context = self._createContext(1) + ciphertext = m2.cipher_update(context, plaintext) + m2.cipher_ctx_free(context) + self.IV = ciphertext[-self.block_size:] + return ciphertext + + def decrypt(self, ciphertext): + AES.decrypt(self, ciphertext) + context = self._createContext(0) + #I think M2Crypto has a bug - it fails to decrypt and return the last block passed in. + #To work around this, we append sixteen zeros to the string, below: + plaintext = m2.cipher_update(context, ciphertext+('\0'*16)) + + #If this bug is ever fixed, then plaintext will end up having a garbage + #plaintext block on the end. That's okay - the below code will discard it. + plaintext = plaintext[:len(ciphertext)] + m2.cipher_ctx_free(context) + self.IV = ciphertext[-self.block_size:] + return plaintext |